dmun's 36" geodesic oven part II

[dmun]

Re: dmun's 36" geodesic oven part II

I decided that the sill plate at the top of the block wall shouldn't be cut, for reasons of the structural stability of the studio.



This means that that it goes through the chimney, and needs two inches of airspace and four inches of masonry between it and the flues. A concrete slug will be formed and poured around the space around the 2x8.



Another construction detail: since the fireplace chimney goes up at an eight degree angle it will get unstable after a while (remember, the flue tiles are supposed to be free-standing). Here is a block of insblock19 used as a slip plane for the flue to lean on. I used three of these in the length of the run. Here, the lower flue tile is mortared, and ready for the placement of the next tile. See that shiny stuff at the bottom of the flue? I put a layer of bubble wrap over the damper, so falling mortar wouldn't glue my damper shut.



Onward,



and upward. Ready for the chimney block run, you can see one at my feet.

[dmun]

Re: dmun's 36" geodesic oven part II

Those chimney blocks were heavy. There was no way for one person to carry them up a ladder, and no room for two.



Here's a winch, improvised from a big winding barrel from my tower clock. There's a pulley mounted at the top of the tower, and another one on the clamp jig, to compound it once. A direct lift was possible with the flue tile shown here, but not the chimney block.



Here's a chimney block on the way up. Every other block got one side cut off, to avoid a running seam going up the chimney, so there were only three full blocks to lift. Three were enough. Even the cut ones were super-heavy.



Swinging sideways into position.

[dmun]

Re: dmun's 36" geodesic oven part II

Moving upward:



A chimney block in position



Another insblock19 slip plane.



As I got higher, I built a platform to work on. Notice the household storage bowl at my feet. I ran out of space for the mortar tub, and after it tipped off a precarious perch, i switched to that bowl to carry up the mortar.



I eventually put a step stool on top of that. In August, window or no window, it was a sweat box in the tower. The air conditioning didn't flow up, of course, and lugging stuff up the ladder into the heat made this one particularly unpleasant job.

[dmun]

Re: dmun's 36" geodesic oven part II

At the tower ceiling,



The flues converge.



I couldn't climb the ladder that high, there wasn't room. I had to climb the scaffold and then scoot sideways to get onto the ladder.



At the top. From here on, it's building from the outside.

[jwnorris]

Re: dmun's 36" geodesic oven part II

Impressive, to say the least.

J W

[dmun]

Re: dmun's 36" geodesic oven part II

Now, to above the roof:



The winch was mounted on the roof sheething, screwed through to the structure underneath.



It was really high up, and perched on that curved decking was a challenge, especially when it got bits of sand and mortar from the masonry, which made it slippery. A hint: Kitty litter buckets aren't engineered for hoisting masonry. That handle died toot sweet.



One thing I did was to build a little work platform on the back side of the chimney, I was able to do the heavy work, like lowering flue tiles, from a level perch.



It did leave me working under grade for the first couple of courses.

[asudavew]

Re: dmun's 36" geodesic oven part II

Just awesome.

What else can I say?

What are you going to do when you are done?

Do you have something else to look forward to?

[dmun]

Re: dmun's 36" geodesic oven part II



Here I am, leaning down to stuff used fiberglass insulation into the block voids, to keep all my mortar from falling down the holes.



Laying out mortar. You notice that the short piece of the big flue tile was put in down here, to make the two stacks level and even. I wanted full pieces up where the weather exposure is the greatest. I've been looking at a lot of chimneys, and you'd be surprised how many are deteriorating at the top.



More mortaring,



and blocks. Note those woven gloves with rough rubber on the palms, I figured out to late that you didn't need to work concrete with bare hands until you bleed.

[dmun]

Re: dmun's 36" geodesic oven part II

Here's another thing I figured out too late:



A jig for filling the spaces between the blocks from above. It's two pieces of "L"-shaped quarter-inch luan, screwed to a piece of two-by-four. Fill and tamp, the job's done.



I start with bricks, to flare out the chimney to it's final size above the flashing. Up to the roof peak.



Another layer of flue tiles in place.



Widening layers of brick. Notice the thin strips of plywood: They are space holders for the flashing, so I don't have to angle grind slots in a precarious place.

[dmun]

Re: dmun's 36" geodesic oven part II

Finally!



Above the roofline, and done with blocks, I can use the Bricky again.



What a difference it makes in the quality of the work.



And speed. Higher,



and higher.

[dmun]

Re: dmun's 36" geodesic oven part II



This is the flashing at the top of the flue tiles, just wrapped around and bolted, with four tabs to establish the top of the slab. This will let me cast a concrete chimney cap and allow for expansion of the flue tile stack.



Here are the last two flue tiles in place.

Almost every chimney, no matter how humble, has some sort of flourish at the top. I think it's a bit of relief that the mason is done with this arduous job.



This was designed to mirror, in a shallow way, the decorative corbels above the oven opening. Also, there are no exposed cuts to deteriorate in this high wear area.



Note how the bricks are tilted at a ten degree angle? This establishes the tilt of the bluestone sills used as edging at the top, tilted to repel standing water.

[dmun]

Re: dmun's 36" geodesic oven part II



More bluestone edging.



The cavity is stuffed with scrap fiberglass insulation, and covered with flashing, to prepare for casting the concrete slug.



Tired? You bet.

[dmun]

First fire!

I tried to embed a youtube video, but it didn't work. Let's try for a clickable link:

First fire video

See if that works, and if it doesn't, here's a picture or two:

[Les]

Re: dmun's 36" geodesic oven part II

Very Cool (hot?) David, and you still have a home Fantastic accomplishment!!!

Les...

[maver]

Re: dmun's 36" geodesic oven part II

Forno. Bravo!